Reassessing the role of grazing lands in carbon-balance estimations: Meta-analysis and review.

Assuming a steady state between carbon (C) gains and losses, greenhouse gases (GHG) inventories that follow a widely used simplified procedure (IPCC Tier 1) tend to underestimate the capacity of soils in grazing-land to sequester C. In this study we compared the C balance reported by (i) national inventories that followed the simplified method (Tier 1) of IPCC (1996/2006), with (ii) an alternative estimation derived from the meta-analysis of science-based, peer-reviewed data. We used the global databases (i) EDGAR 4.2 to get data on GHG emissions due to land conversion and livestock/crop production, and (ii) HYDE 3.1 to obtain historical series on land-use/land cover (LULC). In terms of sequestration, our study was focused on C storage as soil organic carbon (SOC) in rural lands of four countries (Argentina, Brazil, Paraguay and Uruguay) within the so-called MERCOSUR region. Supported by a large body of scientific evidence, we hypothesized that C gains and losses in grazing lands are not in balance and that C gains tend to be higher than C losses at low livestock densities. We applied a two-way procedure to test our hypothesis: i) a theoretical one based on the annual conversion of belowground biomass into SOC; and ii) an empirical one supported by peer-reviewed data on SOC sequestration. Average figures from both methods were combined with LULC data to reassess the net C balance in the study countries. Our results show that grazing lands generate C surpluses that could not only offset rural emissions, but could also partially or totally offset the emissions of non-rural sectors. The potential of grazing lands to sequester and store soil C should be reconsidered in order to improve assessments in future GHG inventory reports.

Psychophysiological aspects of voluntary skilled movement after stroke: a follow-up study.

OBJECTIVES: The aim of the study was to follow the psychophysiological evolution of a self-paced voluntary skilled movement in hemiparetic subjects after ischemic stroke by means of a skilled performance task (SPT). The task consisted in starting a sweep of an oscilloscope trace by pushing one button with the left index finger (trigger point), and in stopping it within a central area on the oscilloscope screen, between 40 and 60 ms (correct performance) after the start of the sweep, by pushing the other button with the right index finger. A SPT yields a considerable amount of information on the electrophysiological components, which reflect pre-programming activity (Bereitschaftspotential--BP), control strategies (Skilled Performance Positivity--SPP) and behavioural response (Correct Performances). The study was also aimed at detecting any longitudinal changes in the psychophysiological pattern, as evaluated by the clinical examination and specific motility scales, that parallel motor recovery. METHODS: Movement related potentials (MRPs) were recorded in 12 control subjects and 9 patients in the acute phase, before the start of neurorehabilitation (time 0), when the patients were able to execute an index finger press with the affected hand. The patients (mean age = 62.33 years, SD = 8.17) presented a mild to moderate central arm paresis caused by a first-ever unilateral supratentorial and subcortical ischemic lesion. The subsequent recordings were carried out respectively 3, 9 and 12 months later. RESULTS: At the first recording, hemiparetic patients achieved a significantly lower percentage of correct performances and had a lower BP amplitude than controls (p < 0.001); SPP was absent. The number of correct performances did not improve significantly during the subsequent recordings. BP amplitude showed a mild increase in the second, third and fourth recordings (p < 0.05), while SPP amplitude revealed a slight improvement at the second and a marked improvement at the third and fourth recordings, when there was no longer a statistically significant difference from controls. CONCLUSIONS: Our findings point to an early recovery of pre-programming activity and a delayed improvement in control activity. The delayed development of control activity in the absence of procedural learning, i.e. skill learning through practice, forces patients to exploit attentional strategies to compensate for their procedural learning impairment. SPT shows that the efficacy of physical therapy aimed at motor ability recovery in hemiparetic patients does not keep up with the slow recovery process of an automatic motor level.

Mutations of thyrotropin receptor isolated from thyroid autonomous functioning adenomas confer TSH-independent growth to thyroid cells.

TSH receptor mutants in the VI transmembrane segment, found in thyroid autonomously functioning adeonomas, have been expressed in differentiated thyroid cells. All mutant receptors constitutively stimulated adenylyl cyclase. The biological activity, measured as cAMP production relative to the wild type receptor, was specific for each mutant in transient and stable transfection assays. Cells expressing these mutants proliferated in the absence of TSH. The rate of growth in the absence of TSH paralleled basal cAMP production for each mutant receptor. Low TSH concentrations stimulated the growth of mutant receptor-expressing cells, and not of the cells expressing the wild type receptor. Also, the entry in the cell cycle and the plating efficiency were markedly stimulated by the expression of the mutant receptors. These data provide a molecular link between the occurrence of TSH receptor mutations and thyroid autonomously functioning adenomas.

Abnormal head nociceptive withdrawal reaction to facial nociceptive stimuli in Parkinson's disease.

INTRODUCTION: Trigemino-cervical-spinal reflexes (TCSRs) are complex brainstem stereotyped nociceptive responses involved in a defensive withdrawal reaction of the head from facial nociceptive stimuli. OBJECTIVE: The present study was undertaken to collect data on possible TCSR abnormalities in idiopathic Parkinson's disease (PD) and investigate any correlation with motor signs and L-DOPA administration. METHODS: TCSRs were registered from the semispinalis capitis and biceps brachii muscles after electrical stimulation of the supraorbital nerve in 18 patients with PD and 24 controls. The latency (L) and area (A), as well as the sensory (ST), painful (PT) and reflex (RT) thresholds were measured during the 'off' and 'on' state, and possible correlations with the UPDRS III total score, selected subscores (tremor, neck rigidity, upper limb rigidity, akinesia, rising from a chair, posture and posture instability) and duration of illness were investigated. RESULTS: Significant changes between controls and PD patients were found in the L, A, PT and RT of TCSRs. These results were not significantly influenced by L-DOPA treatment. A significant correlation was found between neck rigidity, postural instability scores and duration of illness and the TCSR L and A values in PD patients in the 'off' state. CONCLUSIONS: TCSRs abnormalities, combined with dopamine resistance, are consistent with a primary loss of brainstem neurons mediating a complex sensory-motor integration including neck muscle tone and postural control as well as the head withdrawal reaction to the nociceptive stimuli. SIGNIFICANCE: TCSRs may represent a useful tool for the assessment of brainstem sensory-motor function in PD as well as other movement and degenerative disorders.

Multiple sclerosis: getting personal with induced pluripotent stem cells.

Human induced pluripotent stem (iPS) cells can be derived from lineage-restricted cells and represent an important tool to develop novel patient-specific cell therapies and research models for inherited and acquired diseases. Recently, patient-derived iPS cells, containing donor genetic background, have offered a breakthrough approach to study human genetics of neurodegenerative diseases. By offering an unlimited source of patient-specific disease-relevant cells, iPS cells hold great promise for understanding disease mechanisms, identifying molecular targets and developing phenotypic screens for drug discovery. This review will discuss the potential impact of using iPS cell-derived models in multiple sclerosis (MS) research and highlight some of the current challenges and prospective for generating novel therapeutic treatments for MS patients.

Novel mutations of thyrotropin receptor gene in thyroid hyperfunctioning adenomas. Rapid identification by fine needle aspiration biopsy.

Hyperfunctioning thyroid adenomas are clonal neoplasms with the intrinsic capacity of growing and differentiate independently of thyroid-stimulating hormone (TSH). We analysed the mRNA encoding thyrotropin receptor of 11 adenomas obtained by fine needle aspiration biopsy (FNAB) and found 7 mutants all located in three aminoacids clustered in the sixth transmembrane domain of the receptor. These mutations were somatic and specifically present in the tumour tissue. DNA sequence revealed that 80 to 90% of the mutations can be rapidly screened and identified by restriction enzyme analysis of the amplified cDNA obtained from the FNABs. The mutation Thr->Ile was introduced in the wild type receptor and expressed in mouse fibroblasts. These cells constitutively activate the transcription of a reporter gene under the control of cyclic AMP responsive element.

A longitudinal CNV study in a group of five bipolar cyclothymic patients.

The authors carried out a longitudinal study in five subjects with bipolar cyclothymic psychosis, recording contingent negative variations in the same patients in the different phases of illness and under normal clinical conditions. An average voltage decrease was found in the depressive phases and a more conspicuous decrease in the manic phases. Furthermore, an evident postimperative negative variation was present in four subjects during the manic phase. The authors set forth tentative psychological and neurophysiological interpretation of their results.

Brain slow potentials and hypnosis.

Contingent negative variation behavior was studied in 12 voluntary normal subjects in basal conditions and in the hypnotic trance state under different emotional suggestions. A CNV voltage decrease and the appearance of a PINV were observed in the hypnotic state. Furthermore 12 nonhypnotizable control subjects were tested under the same experimental conditions and no CNV modification was found.

Intrafamilial variability in hereditary spastic paraplegia associated with an SPG4 gene mutation.

The authors studied a family with pure autosomal dominant spastic paraplegia (ADHSP) that showed a marked intrafamilial variability in both age at onset and clinical severity, ranging from severe congenital presentation to mild involvement after age 55. They found a novel mutation in the SPG4 gene, which segregates with the disease in six patients. The mutation affects the consensus donor splice site of SPG4 intron 16, resulting in a premature termination codon at amino acid 578. The data confirm the pathologic significance of SPG4 mutations in pure ADHSP and add to the list of known SPG4 allelic variants.

SPG3A: An additional family carrying a new atlastin mutation.

The authors report on a novel frameshift mutation (c.1688insA) in the SPG3A gene resulting in premature translation termination of the gene product atlastin. These data add a new variant to the second disease gene in autosomal dominant hereditary spastic paraplegia (ADHSP) and lend definitive support to its causative role. By combining direct testing of SPAST and SPG3A, at least 50% of ADHSP families can now receive appropriate genetic diagnosis.

Mitochondrial myopathy, parkinsonism, and multiple mtDNA deletions in a Sephardic Jewish family.

The authors describe a family of Sephardic Jews with progressive external ophthalmoparesis, skeletal muscle weakness, and parkinsonism. Autosomal recessive inheritance was suggested by many consanguineous marriages, although a dominant disorder could not be excluded. No linkage to known progressive external ophthalmoparesis locus was found. The presence of cytochrome c oxidase-negative ragged-red fibers, biochemically reduced respiratory chain complexes, and multiple mitochondrial DNA deletions in muscle biopsies from four patients suggested a new mitochondrial disorder of intergenomic communication.

Respiratory chain defects in hereditary spastic paraplegias.

Hereditary Spastic Paraplegias (HSPs) are heterogeneous neurodegenerative disorders whose etiopathogenesis is still unclear. The identification of pathogenic mutations in a gene (SPG7) encoding a mitochondrial metalloprotease suggested that oxidative phosphorylation (OXPHOS) alterations might underlie HSP in a subgroup of patients. We performed clinical, morphological, biochemical, and molecular genetic studies in six HSP patients and in six sporadic patients to investigate OXPHOS in muscle biopsies. Complicated and pure forms were included in our study. Morphological alterations of the type seen in OXPHOS-related disorders were found in three patients. Five patients showed an isolated defect of complex I activity. No mutations in the SPG7 gene were detected. Our results suggest that OXPHOS defects in HSP patients are more common than previously believed.

A simple method for estimating conduction velocity of the spinothalamic tract in healthy humans.

OBJECTIVES: The object of this study was to establish a method for estimating the conduction velocity (CV) of the spinothalamic tract (STT) in relation to clinical application. METHODS: The CV of the STT was estimated by an indirect method based on that reported by Kakigi and Shibasaki in 1991 (Kakigi R, Shibasaki H. Electroenceph clin Neurophysiol 80 (1991) 39). Laser-evoked potentials (LEP) were measured in 8 subjects following hand (LEPH) and foot (LEPF) laser stimulation. The conduction times recorded at the scalp (P340, P400 and N150 potentials) were considered as the summation of peripheral and central components. The peripheral conduction times were calculated by measuring the latency of the electrical cutaneous silent period (from the same stimulus site of LEPs), corrected for F- and M-wave latency values. RESULTS: The CV of the STT ranged between 8.3 and 11.01 m/s and its mean value was found to be approximately 9.87+/-1.24 m/s. The CV of the STT obtained by the N150 latencies overlapped that obtained by the P340/P400 latencies. CONCLUSIONS: Our data suggest that our method appears appropriate and useful for practical clinical purposes, furnishing an additional tool for investigating the physiological function of small-fiber pathways.

Preprogramming and control activity of bimanual self-paced motor task in Parkinson's disease.

OBJECTIVE: The authors investigated programming (Bereitschaftspotential or BP) and control activity (Skilled Performance Positivity or SPP) of a bimanual, sequential, skilled motor act in off-therapy Parkinson's disease (PD) patients. METHODS: We recorded Movement Related Potentials (MRPs) in 12, non-demented, off-therapy parkinsonian patients and in 17 control subjects who were performing a skilled, time-locked motor act, which was not routine in their everyday life but had to be learned: the Skilled Performance Task (SPT). BP, SPP and correct performances were evaluated in grand average waveforms and in sequential blocks. RESULTS: The analysis of correct performances showed that accuracy in PD patients was significantly lower than in the control group and this accuracy did not improve throughout the blocks. A significantly low level of performances was associated with an increased BP amplitude (P<0.05) and decreased SPP amplitude (P<0.05) in PD patients. CONCLUSION: Our findings suggest that skill motor learning is impaired in non-demented unmedicated PD patients. We discuss the view that PD patients may allocate more attentional resources, as suggested by the increased BP amplitude, the decreased SPP amplitude and the low correct performances, in order to perform a new skilled motor act.

L-dopa effects on preprogramming and control activity in a skilled motor act in Parkinson's disease.

OBJECTIVES: The authors investigated whether preprogramming (Bereitschaftspotential, BP) and control activity (skilled performance positivity, SPP) in a bimanual, sequential skilled performance task (SPT) is sensitive to L-dopa administration in non-demented Parkinson's disease (PD) patients. METHODS: Movement related potentials (MRPs) were recorded in 12 non-demented parkinsonian patients before and after acute L-dopa administration, and in 17 control subjects, all of whom were performing SPT for the first time. BP, SPP and correct performances were evaluated both as a grand average and in sequential blocks in order to verify the learning effect. RESULTS: After L-dopa administration the PD patients scored a significantly higher percentage of correct performances (P<0.05), linked to a decreased BP amplitude (P<0.001) and an increased SPP amplitude (P<0.005), than before therapy. Dynamic evaluation through the block analysis did not show any learning effect in off-therapy patients but showed that L-dopa intake improved learning, linked to a BP amplitude decrease (P<0.005) and a SPP amplitude increase (P<0.05). Furthermore, L-dopa minimized differences in the learning trend between off-therapy PD patients and controls. CONCLUSIONS: Our findings suggest that skilled motor learning is impaired in non-demented untreated PD patients. Dopaminergic drug administration seems to restore the ability of PD patients to use more automatic motor strategies, as demonstrated by the electrophysiological and behavioural pattern, which became more similar to that of normal subjects.

Thyrotropin-releasing hormone enhances event-related brain potentials and growth hormone release in man.

Changes in contingent negative variation (CNV), a brain-evoked potential related in arousal, as well as in serum triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), prolactin (PRL), cortisol and growth hormone (GH) levels were recorded in 12 male volunteers receiving either thyrotropin-releasing hormone (TRH) or saline infusion. Only during TRH administration an increase in CNV (P less than 0.02) and, 30 min later, in GH (P less than 0.05) occurred; thyroid hormones and PRL increased as well, in the absence of any correlation with CNV areas. Cortisol was not affected by TRH. As dopamine (DA) agonistic drugs notoriously increase both CNV areas and GH levels and experimental evidence for prodopaminergic properties of TRH has accumulated in animal models, a possible explanation of the results here presented might be the activation of DA pathways by TRH also in the human.

Electrophysiological (EEG, BAEP, VEP) study in patients with beta-thalassemia major.

Twenty-four patients affected by beta-thalassemia major were studied by means of combined EEG, VEP and BAEP recordings. All the subjects were treated with regular blood transfusions and chelating therapy (DFO). An elevated incidence of EEG abnormalities (70.8%) consisting of diffused slow waves and/or diffused small sharp spikes was seen. VEP P100 latency was abnormally prolonged in eight patients (33.3%). Furthermore, a voltage increase of N75-P100 (29%) and P100-N145 (33.3%) VEP components was observed. Mean latency and voltage values were significantly increased when compared with those of a control group. No BAEP alterations were observed. No correlations were found between electrophysiological data, serum ferritin levels and transfusional treatment duration. The possible mechanisms involved in provoking such electrophysiological abnormalities are discussed.

Pilomotor epilepsy.

The case is reported of a patient presenting pilomotor seizures as the initial symptom of a tumour of the deep temporal lobe. Six other cases had previously been reported with the same type of seizures. The responsible lesion was often a tumour in deep temporal lobe and the distribution of the piloerection attacks was almost always ipsilateral. Pilomotor seizures deserve a definite role in the nosography of partial epilepsy.